This description relates in general to the field of a micro gripper and method for manufacturing the same.
Recently, with the advancement of small-size and light-weighted electronic components, a microstructure, a micro sensor or an actuator has been developed using a semiconductor process.
Further, with an increased interest in the human body, research on operation of the bio cells has been advanced.
However, equipment, which can move, fix and combine objects such as the microstructure or the bio cells, has not been actually provided.
Under these circumstances, study for a micro gripper which is precisely movable so as to enable micro electronic components, such as the microstructure and the actuator, and an object such as the bio cell to be fixed, moved and combined is needed.
The micro gripper is a mechanism that can grip or release a micro object at a desired position, for the purpose of assembly of micro components and micro-position control.
A micro gripper driving method may be classified into a thermal driving method, an electrostatic driving method, a piezoelectric driving method, a pneumatic driving method and a hybrid driving method.
The thermal drive micro gripper has disadvantages such as a high driving voltage, energy consumption and difficulty in application to a bio-field, because an object using thermal expansion of the object due to the Joule heat generated from an applied voltage is gripped.
The electrostatic micro gripper performs the gripping of an object using electrostatic force between two applied charges. The electrostatic micro gripper has disadvantages such as driving displacement to a voltage and weak gripping force, and may not properly release an object due to stiction caused by electrostatic force, after gripping.
The piezoelectric micro gripper has advantages such as minute driving control and strong gripping force, but there exists a need to minimize the specific hysteresis shape of a piezoelectric object.
The pneumatic micro gripper may be applied to a variety of fields such as the bio-field, without special energy sources such as a voltage because it uses the pneumatic.
Further, the pneumatic micro gripper may grip an object appropriately since it can be manufactured in the shape of a finger joint.
However, as the pneumatic micro gripper has a weak gripping force in case of gripping an object, it is difficult to perform pneumatic control and process, and it is necessary for separate package processes for allowing the air to enter, thereby increasing entire manufacturing cost.
FIG. 1 is a schematic perspective view illustrating a conventional micro gripper 10.
The micro gripper 10 is composed of structures 11 and 12 of a pair of gripper jaws that are spaced while facing to each other.
The micro gripper 10 can manipulate micro components and bio cells precisely by performing the gripping by means of an actuator.
The actuator mainly uses a pneumatic driving method.
FIG. 2a or FIG. 2b is a schematic cross-sectional view explaining a driving method of the conventional micro gripper.
As shown in FIG. 2a, structures 11 and 12 of a pair of gripper jaws grip a target object 20 by narrowing a distance between the structures 11 and 12 by the driving of the actuator.
Afterwards, a force for gripping the target object 20 is released by broadening the distance between the structures 11 and 12 of the gripper jaws.
At this time, as shown in FIG. 2b, when the micro gripper grips a target object 20 below 100 μm, the electrostatic force is generated between the target object 20 and the structures 11 and 12 of the gripper jaw and thus a stiction phenomenon where the target object becomes stuck to the structures 11 and 12 of the gripper jaw is generated.
As described above, when using the conventional micro gripper, it is difficult to release the micro object at a desired position because it is difficult to grip or control the micro object.